In the year covered by this application I plan to (a) study tyrosinase activty in the skin of albino mice and elucidate differences between "albino tyrosinase" and that in normally pigmented skin and hair; and (b) partially purify and characterize tyrosinase derived from foreskins and compare the tyrosinases in skins from white and black individuals. BIBLIOGRAPHIC REFERENCES: S.H. Pomerantz and I.G. Ances. Tyrosinase activity in human skin. Influence of race and age in newborns. J. Clin. Invest.,55, 1127 (1975). A. Tsafriri, S. H. Pomerantz, and C.P. Channing. Follicular control of oocyte maturation in Proceedings of a Serano Symposium on "Ovulation in the Human", Academic Press, N.Y.(in press 1975).